Vibratory road-roller

ABSTRACT

A VIBRATORY ROAD-ROLLER HAS AN IMPROVED VIBRATOR SHAFT MOUNTING ALONG THE OPERATION OF THE MACHINE WITH HIGH INERTIA-FORCES. THIS IS EFFECTED BY MOUNTING THE VIBRATOR SHAFT BEARINGS IN ANNULAR PLATES PERMITTING AXIAL MOVEMENT OF THE SHAFT WITHOUT RADIAL MOVEMENT.

0d 5, 1971 H. ENGl-:LHARD VIBHATURY RQAD-ROLLER 2 Sheets-Sheet 1 f FiledApril 16, 1969 In V c 7210/ He wz Enge Zmfcl JL A :E f :fr .m i u 1p I-n Q W l N l f nw f lill 1f|| in \\M l H t m w NP E 1: I- a m E l m) Nldd S f l l 1 HUI NN 2 E oct. s, 1971 H. ENGELHARD 3,610,118

VIBRATORY ROAD-ROLLER Filed April 16, 1969 2 Sheets-Sheet 2 .Tnyf 72 'ZwA Heavvz EngQZ/kz/jcl/ United States Patent O 3,610,118 VIBRATORYROAD-ROLLER Heinz Engelhard, Hameln-Auf dem Anger, Germany,

assignor to ABG-Werke GmbH, Hameln-Am Damm,

Germany Filed Apr. 16, 1969, Ser. No. 816,512 Claims priority,application Germany, Apr. 19, 1968, P 17 59 301.0 Int. Cl. E01c 19/28U.S. Cl. 94-50 R 3 Claims ABSTRACT OF THE DISCLOSURE A vibratoryroad-roller has an improved vibrator shaft mounting along the operationof the machine with high inertia-forces. This is effected by mountingthe vibrator shaft bearings in annular plates permitting axial movementof the shaft without radial movement.

The invention relates to a vibratory road-roller capable of producingvariable inertia-forces and having an out-ofbalance shaft supported ateach end in the interior of the roller body.

In order to render the use of vibration road-rollers, primarily inroad-construction, more economical, the outof-balance masses have beendesigned to be displaceable in order to enable operations to be carriedout with variable inertia-forces. Practice has shown that whencompacting cohesive types of earth and broken rock material a very largeinertia-force at a low frequency gives the most favorable compactingperformance. On the other hand, a low frequency and a high inertia-forcein the vibration road-roller leads to undesirable breaking up of thesurface of the ground if the number of passes of the roadroller isincreased and when non-cohesive types of ground are being compacted.This phenomenon is countered by using a higher frequency and a smallerinertia-force during the last passes of the road-roller or when theground is of the non-cohesive kind.

Thus, it would be desirable to have a vibratory roadroller which enablesoperations to be carried out on the one hand with the greatest possibleinertia-forces applied at low frequency and, on the other, with lowerinertiaforces but applied at high frequencies.

The problem of mounting the out-of-balance shaft has hitherto set limitsas regards the very high inertia-forces required, in that with bearingelements of appropriately increased size insoluble lubrication problemshave been encountered, particularly as it has been necessary to fulfilthe additional requirement that operations had to be carried outsubstantially without the need for maintenance, although highfrequencies were used. Furthermore, with bearing elements of increasedsize, the slightly oblique positions of the shaft caused by deflectionsof the vibration shaft during the production of very largeinertiaforces, would result in pressure at the edges of the bearings,which pressure could not be countered by the use of appropriatematerials.

The object of the invention therefore is firstly to permit theproduction of low frequency inertia-forces of an order of magnitudegreater than those at present obtainable, while taking this problem ofmounting the out-of-balance shaft into account, and secondly to providea construction which can enable operations to be carried out using asmall inertia-force at high frequency.

According to the present invention there is provided a vibratoryroad-roller capable of producing variable inertia-forces, and having anout-of-balance shaft supported at each end in the interior of the rollerbody in a corresponding support comprising a pair of bearings disposedside by side in a common supporting housing which is suspended in anannular plate secured by its outer edge to the roller body, each of theplates being rigid in the radial direction but permitting slight play inthe movement of the supporting housing in the axial direction.

The division of the supports into two bearings disposed side by saidenables their individual bearing capacities to be utilized for producinginertia-forces in excess of the present-day standardized order ofmagnitude, without thereby encountering insoluble lubrication problems.

The inclined positions of the out-of-balance shaft, occuring when largeinertia-forces are used, and the associated pressures at the edges ofthe bearing elements, hitherto of one-piece construction, are taken intoaccount by the suspension of the supporting housings for the doublebearings in the annular plates which are rigid in the radial directionbut permit slight play in movement in the axial direction. The bearingsare thus able automatically to adapt themselves to the unavoidableinclined positions or deflections of the out-of-balance shaft,especially when excessive inertia-forces are present.

Preferably the bearings are roller bearings.

The required properties can be imparted to the annular plates by, forexample, providing recesses in them which reduce the rigidity in theaxial direction. A further solution consists in forming each annularplate from a number of disc-shaped laminations rather than as a singlecomponent. The various laminations can be advantageously combined toform an annular element of fan-shaped cross-section.

The out-of-halance shaft is powered at different frequencies preferablyby means of a reversing drive or a reversing gear. The out-of-balanceshaft can thus be changed over from anti-clockwise to clockwise movementby means of a simple switching operation. By providing rotatably mountedimbalance masses on the out-of-balance shaft in the vicinity of stops,the vibration roller can be made to operate at high frequency and withreduced inertia-force during anti-clockwise movement and at lowfrequency and with a very high inertia-force during clockwise movement.

The invention will now be described in greater detail with reference tothe accompanying drawings, of which:

FIG. 1 shows a longitudinal section through a vibratory roller havingbearing supports and an out-of-balance arrangement in accordance withthe invention;

FIG. 2 shows a section on line A-A through the outof-balance shaft foranti-clockwise movement and high frequency in the out-of-balance shaft;

FIG. 3 shows the same section through the out-ofbalance shaft forclockwise movement and low frequency;

FIG. 4 is a plan view of an annular plate according to the invention;

FIG. 5 is a plan view of another annular plate according to theinvention;

FIG. 6 is a sectional view taken along the line 6 6 of FIG. 5; and

FIG. 7 is a sectional view similar to FIG. 6 but showing a plurality ofplates arranged in the manner of lamellae.

The numeral 1 indicates the roller body and 2 the out- Of-balance shaft.The out-of-balance shaft 2 is mounted at both ends in bearing supportswhich each comprise two cylindrical roller bearings, 3, 4 and 5, 6respectively, disposed side by side. Associated with the pairs ofbearings are supporting housings 7, 8 which are suspended in annularplates 9, 10; the supporting housings 7, 8 are secured to the inneredges `9, 10 of these plates and the outer edges 9, 10 0f the plates aresecured, by means of ring inserts 18, 19 to the end-walls 20, 21 of theroller body 1. The ring inserts 18, 19 also serve to secure thejournal-covers 22, 23 of the roller body 1.

Firmly keyed on to the out-ot-'balance shaft 2 are two imbalance masses11, 12, which are provided With a dog 13. Associated with each of theiixed imbalance masses 11 and 12 is a rotatably mounted imbalanceelement 14, 15 each of which is provided with two resilient stops 16,17.

yWhen the vibratory roller is driven at high frequency and moves in theanti-clockwise direction as shown in FIG. 2, the dogs 13 of the xedimbalance masses 11, 12 carry the rotatably mounted imbalance elements14, 15 beyond the resilient stops 17, so that the rotatably mountedimbalance elements 14, 15 have the effect of reducing the totalinertia-force.

-When the vibratory roller is driven at low frequency and moves in aclockwise direction, as shown in FIG. 3, the dogs 13 on the xedimbalance masses 11, 12 move the rotatably mounted imbalance elements 14and 15 beyond the resilient stops 16, so that the rotatably mountedimbalance elements 14, 15 have the eiect of raising the totalinertia-force.

By dimensioning and/or shaping the annular plates 9', in such a way thatthey can be regarded as practically rigid in the radial direction andpermit play in the movement of the supporting housings 7, 8, suspendedtherefrom, in the axial direction, the effect is achieved of enablingthe pairs of roller bearings 3, 4 and 5, 6 to adapt themselves to theinclined positions of the out-of-balance shaft, so that no excessivepressures can occur at the edges of the bearings, and the full bearingcapacity of the roller bearings can thus be utilized. The consequence ofthis is that such bearing supports can withstand inertiaforces wellabove the present norm, and there is thus provided the possibility ofvibratory rollers operating at low and high rotational speeds usinginertia-forces hitherto regarded as being unattainable.

Also, FIGS. 4 and 5, respectively, show annular plates 25 and 26 eachhaving respective cutout portions 25a and 26a for reducing the rigidityof each plate in its axial direction. FIG. 7 is a sectional view similarto FIG. 6 except that a plurality of plates 26 are shown which may besecured together through apertures 26b for producing a flexible lamellaeof annular plates.

I claim:

1. A vibration roller capable of producing `variable inertia forces,comprising a roller body, an axial out-ofbalance shaft mounted atopposite ends within said roller body, eccentric mass elements securedto said shaft within said body, bearing means for mounting each saidopposite end, each said bearing means comprising a double bearing unit,each having a pair of bearings therein, each of said unit pairs beingadjacent one another and each pair being lprovided in a commonsupporting housing, a thin annular plate member surrounding each saidhousing and being disposed substantially midway between the oppositeends of said housing perpendicularly to saidaxial shaft, each said platemember being mounted at its inner annular edge to each said housing andat its outer annular edge to the inside of said roller body, each saidplate being rigid in a radial direction and tiexible in its axialdirection, thereby permitting a wobblng movement of said shaft oppositeends in relation to the bending of said shaft during its rotation withsaid eccentric mass elements thereon, whereby each said pair of rollerbearings are capable of adapting themselves to the inclined positions ofsaid bending shaft at said opposite ends.

2. Vibration roller according to claim 1, in which the annular plateconsists of a multiplicity of annular plates arranged in the manner oflamellae.

3. Vibration roller acording to claim 2, in which the lamellae of theannular plates have a fan-shaped cross section. t References CitedUNITED STATES PATENTS 2,671,386 3/1954 Kerridge 94-50 3,052,166 9/1962Thrun 94-48 3,145,631 8/1964 Green 94-50 3,267,825 8/1966 Owen 94-503,303,762 2/1967 Jennings 94-50 3,427,940 2/196'9 MacDonald 94-503,437,019 4/ 1969 Peterson 94-50 FOREIGN PATENTS 947,616 8/1956 Germany94-50 NILE C. BYERS, JR., Primary Examiner U.S. C1. X.R. 94-50 RV

